Press working simulator

ABSTRACT

A press working simulator according to an aspect of the present disclosure includes: a robot program storage section that stores a robot program that instructs a robot how to move; a press program storage section that stores a press program that instructs a press machine how to move; a profile data setting section that causes the press program storage section to store a press program according to profile data that records what position a die is in at each time point when the press machine is actually moved; a model placing section that places three-dimensional models of a workpiece, the robot, and the press machine in a virtual space; a press movement processing section that causes the three-dimensional model of the press machine to move according to the press program; and a robot movement processing section that causes the three-dimensional model of the robot to move according to the robot program.

This application is based on and claims the benefit of priority fromJapanese Patent Application No. 2019-116994, filed on Jun. 25, 2019, thecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to press working simulation.

Related Art

A known press working system includes a press machine that presses aworkpiece while holding the workpiece between a pair of dies (movableand fixed dies); and a robot that supplies the workpiece to the pressmachine and takes out the pressed workpiece. To improve the productivityof such a press working system, it is desirable to cause the pressmachine and the robot to coordinately move so that the robot suppliesand takes out the workpiece before the movable die in the press machinereaches the top dead center and after a certain space is formed betweenthe movable and fixed dies.

As for the technique for causing a press machine and a robot to movecoordinately, for example, Patent Document 1 discloses a method forcontrolling a transfer robot for reciprocating machines so that, whenthe transfer robot transfers a workpiece between adjacent ones of thereciprocating machines arranged in line, the transfer section of thetransfer robot does not interfere with the movement sections of thereciprocating machines, the method including: sequentially detectingpositions of the movement sections during working by the reciprocatingmachines; and controlling the movement of the transfer section of thetransfer robot based on a data table that stores relationships betweenpositions of the movement sections and positions of the transfer sectionwhere it does not interfere with the movement sections.

Patent Document 1: Japanese Unexamined Patent Application, PublicationNo. 2005-216112

SUMMARY OF THE INVENTION

In the technique of Patent Document 1, the data table storesrelationships that have been previously calculated between phase anglesor a main gear in the press machine and coordinate positions of acrossbar in the transfer robot where the crossbar is on the verge ofinterfering with the movable die. In such a press working system,however, any component other than the crossbar in the transfer robot orthe workpiece held by the transfer robot may interfere with the pressmachine. Therefore, a need exists for a technique that makes it possibleto check in detail whether or not a robot program is suitable for apress working system including a press machine and a robot which workcooperatively.

An aspect of the present disclosure is directed to a press workingsimulator that simulates and checks operation of a press working systemincluding a robot, that transfers a workpiece and a press machine thatworks the workpiece while holding the workpiece between dies, the pressworking simulator including: a robot program storage section that storesa robot program that instructs the robot how to move; a press programstorage section that stores a press program that instructs the pressmachine how to move; a profile data setting section that causes thepress program storage section to store the press program according toprofile data that records what position the die is in at each time pointwhen the press machine is actually moved; a model placing section thatplaces three-dimensional models of the workpiece, the robot, and thepress machine in a virtual space; a press movement processing sectionthat causes the three-dimensional model of the press machine to moveaccording to the press program; and a robot movement processing sectionthat causes the three-dimensional model of the robot, to move accordingto the robot program.

The press working simulator according to the present disclosure makes itpossible to check in detail whether or not a robot program is suitablefor a press working system including a press machine and a robot whichwork cooperatively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a configuration of a press workingsimulator according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram showing three-dimensional models placed bya model placing section in the press working simulator of FIG. 1;

FIG. 3 is a graph showing an example of profile data stored by a profiledata setting section in the press working simulator of FIG. 1;

FIG. 4 a graph showing modified examples of a press program, which arecreated by a press program modification section in the press workingsimulator of FIG. 1;

FIG. 5 is a graph showing a modified example of a press program, otherthan those in FIG. 4, which is created by the press program modificationsection in the press working simulator of FIG. 1;

FIG. 6 is a schematic diagram showing examples of target positionsaccording to a robot program stored by a robot program storage sectionin the press working simulator of FIG. 1; and

FIG. 7 is a flowchart showing a procedure of simulation by the pressworking simulator of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings. FIG. 1 is a schematic diagram showing aconfiguration of a press working simulator 1 according to an embodimentof the present disclosure. The press working simulator 1 may beimplemented by causing a computer including, for example, a CPU, amemory, and other components to execute an appropriate program.

The press working simulator 1 includes a virtual space informationstorage section 11, a model placing section 12, an interferencedetection section 13, a press program storage section 14, a pressmovement processing section 15, a profile data setting section 16, apress program modification section 17, a robot program storage section18, a robot movement processing section 19, a template program settingsection 20, and a robot program modification section 21. Thesecomponents are distinguishable in terms of function and do not need tobe clearly distinguishable according to program structure.

The press working simulator 1 is a system that reproduces operation of apress working system in a virtual space to simulate and check theoperation, in other words, a system that simulates operation of a pressworking system. The pressing working simulator may reproduce operationof a press working system including: one or more press machines thatwork a workpiece while holing it between dies (movable and fixed dies);and a robot that holds and transfers a workpiece, supplies the workpieceto the press machine, and takes out the workpiece from the pressmachine. The press working system may be an apparatus including pluralpress machines and a robot and configured to shape a single workpiecestep by step with the press machines and to cause the robot to transferthe workpiece from an upstream one to a downstream one of the pressmachines. The press working simulator 1 may be a robot programmingsystem that creates, based on a result of simulation, a robot programthat enables a robot to move properly in a press working system.

The virtual space information storage section 11 stores informationabout three-dimensional models placed in a virtual space. Specifically,the virtual space information storage section 11 stores informationabout three-dimensional models of a workpiece, a press machine, and arobot, which are placed by the model placing section 12 described below.

As illustrated in FIG. 2, the model placing section 12 places athree-dimensional model of a workpiece W, three-dimensional models ofpress machines P, and a three-dimensional model of a robot R in avirtual space, in other words, causes the virtual space informationstorage section 11 to store information about the three-dimensionalmodels. Therefore, the model placing section 12 stores informationnecessary for making three-dimensional models including the geometriesand axial arrangements of the workpiece W, the press machines P, and therobot R.

These three-dimensional models may be made by modeling only componentsthat potentially interfere with one another in the actual press workingsystem and are necessary for the calculation of the operation of thesystem. As shown in FIG. 2, a specific example or the three-dimensionalmodel of the press machine P may include only dies (a movable die M1 anda fixed die M2) and tables (a movable table T1 and a fixed table T2 thatsupport the dies M1 and M2. The three-dimensional model of the robot Rmay include a base B, plural arms A1, A2, and A3, and a work W-holdinghand H, which are connected together.

The interference detection section 13 detects interference between thethree-dimensional models of the workpiece W, the press machines P, andthe robot R, in other words, determines whether or not the robot R canmove properly. Specifically, the interference detection section 13 maybe configured to determine any coordinates in an overlap zone betweentwo or more three-dimensional models and to determine three-dimensionalmodels containing such coordinates.

The press program storage section 14 stores a press program thatinstructs the press machines P how to move.

The press movement processing section 15 causes the press machines P tomove, specifically, causes components of the press machines P, such asthe movable dies M1 and the movable tables T1, to move in the virtualspace according to the press program stored in the press program storagesection 14.

The profile data setting section 16 causes the press program storagesection 14 to store a press program according to profile data thatrecords what positions the movable dies are in at each time point whenthe real press machines are actually moved. Specifically, the profiledata setting section 16 stores profile data about the real pressmachines and initializes the press program, which is to be stored in thepress program storage section 14, in such a way that the press programinstructs how to move in agreement with the profile data about theactual press machines.

FIG. 3 shows an example of profile data stored by the profile datasetting section 16. In the example shown, the position of the movabledie is represented by the angle by which a drive shaft rotates to drivethe movable die, with the origin defined as the bottom dead center atwhich the movable die comes into contact with the fixed die duringpressing.

The press program modification section 17 modifies the press programstored in the press program storage section 14 according to anydifference between the press machine movement conditions to be checkedand the press machine movement conditions under which the profile datais recorded while the real press machines are moved.

If the press working cycle for the press machines to be checked isdifferent from that during the recording of the profile data, the pressprogram modification section 17 may modify, as illustrated in FIG. 4,the press program in the press program storage section 14 into a pressprogram according to a profile formed by expanding or compressing theprofile data in the time axis direction. FIG. 4 shows an example (solidline) in which the press working cycle is reduced to ½ by expanding theprofile data (indicated by the broken line) by two times in the timeaxis direction, and an example (alternate long and short dash line) inwhich the press working cycle is increased to two times by compressingthe profile data into ½ in the time axis direction.

Alternatively, the press program modification section 17 may beconfigured to modify, for example, the length of time during which themovable die is at the top dead center and the moving speed of themovable die, as shown in FIG. 5. FIG. 5 illustrates an example in whichthe rise in the graph is shifted parallel to the right to delay thetiming at which the movable die moves from the bottom dead center towardthe top dead center so that the graph is deformed to have a more linearrise, which results in a shorter period of time during which the movabledie is at the top dead center. To make such a modification, the pressprogram modification section 17 may be configured to display a profiledata graph on a screen and allow the user to alter the graph by using amouse or other device so that the press program is modified.

The robot program storage section 18 stores a robot program thatinstructs the robot how to move. The robot program is written accordingto a protocol similar to that used for programming real robots.Specifically, the robot program may specify target positions (teachingpoints) at which reference points such as a hand should be located andtime points at which the reference points should be located at thetarget positions.

According to the robot program stored in the robot program storagesection 18, the robot movement processing section 19 moves the robot R,specifically, each of components B, A1, A2, A3, and H of the robot R andthe workpiece W held by the robot R, in the virtual space.

The template program setting section 20 causes the robot program storagesection 18 to store, as an initial version of the robot program, atemplate program that instructs the robot R how to move basically. Forthis purpose, the template program setting section 20 stores a presettemplate program.

FIG. 6 schematically shows an example of the template program stored bythe template program setting section 20. This template program is arobot program that causes the robot R to move so as to take out theworkpiece W from a fixed die M2 in an upstream press machine P and placethe workpiece W on a fixed die M2 in a downstream press machine P, inwhich eight target positions Q1 to Q8 are provided at which referencepoints for a hand H are to be located.

According to the template program of FIG. 6, the hand H of the robot Buses a first target position Q1 as a starting point and moves to asecond target position Q2 above the fixed die M2 in the upstream pressmachine P. At a third target position Q3, the hand H comes into contactwith the workpiece W and holds the workpiece W and then moves to afourth target position Q4 to take out the workpiece W from the fixed dieM2. The hand H then moves to a fifth target position Q5 to place theworkpiece W above the fixed die M2 in the downstream press machine P.The hand H then moves to a sixth target position Q6 to place theworkpiece W on the fixed die M2. After the hand H releases the workpieceat the sixth target position Q6, the hand H moves to a target positionQ7 to go away from the fixed die M2 and the workpiece W. The hand H thenmoves to a target position QS so that the robot R goes away from an areawhere the movable die M1 and the movable table T1 are to move.

The robot program modification section 21 modifies the robot program toprevent interference between the robot R and the press machines P, whichhas been detected by the interference detection section 13 when thepress movement processing section 15 causes the press machines P to moveaccording to the press program and the robot movement processing section19 causes the robot R to move according to the robot program. Thedetection of the interference by the interference detection section 13and the modification of the robot program by the robot programmodification section 21 may be made per unit movement, which correspondsto the movement of the robot R and the press machine P performed duringa travel from a target position Qn (n is the target position number) toa next target position Qn+1 according to the robot program.

If it is detected that the robot R or the workpiece W interferes withthe press machine P during the travel from the target position Pn to thetarget position Qn+1, the robot program modification section 21 modifiesthe robot program to change the coordinates of the target position Qn+1.If the coordinates of the target position Qn+1 are changed, the pressworking simulator 1 may cause the press movement processing section 15and the robot movement processing section 19 to make movement again fromthe target position Qn to the changed target position Qn+1 and cause theinterference detection section 13 to check whether or not interferenceoccurs between the robot R or the workpiece U and the press machine P.In other words, the press working simulator 1 may modify the robotprogram at each target position so as to prevent interference betweenthe robot R or the workpiece U and the press machine P.

When the interference detection section 13 detects interference, therobot program modification section 21 preferably shifts the targetposition Qn+1 in a direction in which the movable die M1 moves, morespecifically, in a direction in which the movable die M1 approaches thefixed die M2. If the target position Qn+1 is shifted in the direction inwhich the movable die M1 moves, the direction in which the workpiece Wis placed onto the fixed die M2 and the direction in which the workpieceU is taken out from the fixed die M2 can remain unchanged.

Usually, the direction in which the movable die M1 moves is the same asthe direction in which the workpiece U is placed onto the fixed die M2and the direction in which the workpiece U is taken out from the fixeddie M2. Therefore, the robot program modification section 21 can shiftthe target position Qn+1 toward the previous target position Qn or thenext target position Qn+2. The amount of shift of the target positionQn+1 may be a constant distance or a constant proportion of the distancebetween the target position Qn+1 and the previous target position Qn orthe next target position Qn+2.

The amount of shift of the target position Qn+1 to prevent theinterference between the robot R or the workpiece W and the pressmachine P should be determined within a range where the workpiece W doesnot interfere with the fixed die M2. Therefore, the amount of shift mayhave a lower limit set to the distance between the shifted targetposition Qn+1 and the previous target position Qn or the next targetposition Qn+2. If such a lower limit is not enough for the shift of thetarget position Qn+1 to prevent the interference between the robot R orthe workpiece W and the press machine P, the previous target position Qnor the next target position Qn+2, whose relationship with the targetposition Qn is not in the direction of movement of the die, may beshifted in a direction in which the movable die M1 goes away from thefixed die M2. This makes it possible to prevent the hand H fromovershooting toward the movable die M1 during the passage through thetarget position Qn while preventing the interference between the robot Ror the workpiece W and the press machine P.

In a specific example, if interference is detected during the movementfrom the first target position Q1 to the second target position Q2according to the template program of FIG. 6, the robot programmodification section 21 may shift the second target position Q2 in adirection toward the fixed die M2, that is, toward the third targetposition Q3. This makes it possible to prevent interference during themovement from the first target position. Q1 to the second targetposition Q2.

If interference is detected during the movement from the third targetposition Q3 to the fourth target positon Q4 according to the templateprogram of FIG. 6, the robot program modification section 21 may shiftthe fourth target position Q4 in a direction toward the fixed die M2,that is, toward the third target position Q3. Similarly, if interferenceis detected during the movement from the fourth target position Q4 tothe fifth target position Q5, the robot program modification section 21may shift the fifth target position Q5 toward the sixth target positionQ6, and if interference is detected during the movement from the sixthtarget position Q6 to the seventh target position Q7, the robot programmodification section 21 may shift the seventh target position Q7 towardthe sixth target position Q6.

The robot program modification section 21 may further adjust themovement speed or acceleration of the robot R in the robot program. Whenthe movement speed or acceleration of the robot R is increased, the timetaken for the robot R to move can be shortened. This allows the robot Rto transfer the workpiece during a period of time when the distancebetween the movable die M1 and the fixed die M2 is relatively large inthe press machine P, so that the interference between the robot R or theworkpiece W and the press machine P can be prevented under variousconditions.

Next, FIG. 7 shows a procedure in which the press working simulator 1modifies the robot program. The modification of the robot programincludes placing three-dimensional models (step S1); setting profiledata (step S2); modifying a press program (step S3); writing a templateprogram (step S4); moving three-dimensional models (step S5); checkingwhether interference occurs (step S6); modifying a robot program (stepS7); and determining whether to end the program (step S8).

The step S1 of placing three-dimensional models may include causing themodel placing section 12 to place three-dimensional models of the robotR, the press machines P, and the workpiece W in a virtual space, whichis virtually created by the virtual space information storage section11.

The step S2 of setting profile data may include causing the profile datasetting section 16 to instruct the press program storage section 14 tostore a press program based on profile data.

The step S3 of modifying the press program may include modifying thepress program, which is stored in the press program storage section 14,according to the requirements for press working to be checked.

The step S4 of writing a template program may include causing thetemplate program setting section 20 to write and store a templateprogram as an initial version of a robot program into the robot, programstorage section 18.

The step S5 of moving three-dimensional models may include causing thepress movement processing section 15 to move a three-dimensional modelof the press machine P according to the press program stored in thepress program storage section 14 and causing the robot movementprocessing section 19 to move three-dimensional models of the robot Rand the workpiece W according to the robot program stored in the robotprogram storage section 18.

The step S6 of checking whether interference occurs may include causingthe interference detection section 13 to check whether or notinterference occurs between the three-dimensional model of the pressmachine P and the three-dimensional model of the robot R or thethree-dimensional model of the workpiece W. If the interferencedetection section 13 detects interference, the process proceeds to stepS7, and if the interference detection section 13 does not detectinterference, the process proceeds to step S8.

The step S7 of modifying the robot program may include causing the robotprogram modification section 21 to modify the robot program, which isstored in the robot program storage section 18, so that the interferencebetween the three-dimensional model of the press machine P and thethree-dimensional model of the robot R or the three-dimensional model ofthe workpiece W is prevented. If the robot program is modified in stepS7, the process returns to step S5 in which the three-dimensional modelsare moved according to the robot program.

The step S8 of checking whether to end the program may include checkingwhether or not the press program and the robot program are executed tocompletion. If the press program and the robot program are executed tocompletion, the process is ended. If part of at least one of the pressprogram and the robot program remains unexecuted, the process returns tostep S15 in which the three-dimensional models are moved according tothe remaining part of the program.

The press working simulator 1 includes the profile data setting section16 which causes the press program storage section 14 to store a pressprogram according to profile data that records what position the die M1or M2 is in at each time point when the real press machine P is actuallymoved. Therefore, the three-dimensional model of the press machine P canbe moved to approximate the movement of the real press machine P.Therefore, the press working simulator 1 can accurately check in detailwhether or not the robot program is suitable.

In addition, the press working simulator 1, which includes theinterference detection section 13 and the robot program modificationsection 21, can function as a robot programming system to automaticallycreate an appropriate robot program.

Furthermore, the press working simulator 1 includes the template programsetting section 20 that causes the robot program storage section 18 tostore, as an initial version of the robot program, a template programthat instructs the robot R how to move basically, which makes itpossible to easily and reliably create an appropriate robot program.

While embodiments of the press working simulator according to thepresent disclosure have been described above, it will be understood thatthe embodiments are not intended to limit the press working simulatoraccording to the present disclosure. It will also be understood that theadvantageous effects shown in the above embodiments are mere examples ofthe most preferred effect produced by the press working simulatoraccording to the present disclosure and are not intended to limit theadvantageous effects of the press working simulator according to thepresent disclosure.

The press working simulator according to the present disclosure may haveany configuration for the robot program and may have any configurationto detect interference. The press working simulator according to thepresent disclosure may be configured to display the movement ofthree-dimensional models on a screen, allow the user to observeinterference on the screen, and allow the user to determine how therobot program should be modified to prevent interference.

The press working simulator according to the present disclosure mayplace any number of three-dimensional models of press machines androbots in the virtual space. For example, the press working simulatoraccording to the present disclosure may be configured to move, in avirtual space, a three-dimensional model of a robot that supplies aworkpiece to a single press machine and takes out the workpiece from thepress machine. In the press working simulator according to the presentdisclosure, all press machines and robots placed in the virtual spacemay move coordinately on a single time axis.

EXPLANATION OF REFERENCE NUMERALS

-   1: Press working simulator-   11: Virtual space information storage section-   12: Model placing section-   13: Interference detection section-   14: Press program storage section-   15: Press movement processing section-   16: Profile data setting section-   17: Press program modification section-   18: Robot program storage section-   19: Robot movement processing section-   20: Template program setting section-   21: Robot program modification section

What is claimed is:
 1. A press working simulator that simulates andchecks operation of a press working system comprising a robot thattransfers a workpiece and a press machine that works the workpiece whileholding the workpiece between dies, the press working simulatorcomprising: a robot program storage section that stores a robot programthat instructs the robot how to move; a press program storage sectionthat stores a press program that instructs the press machine how tomove; a profile data setting section that causes the press programstorage section to store the press program according to profile datathat records what position the die is in at each time point when thepress machine is actually moved; a model placing section that placesthree-dimensional models of the workpiece, the robot, and the pressmachine in a virtual space; a press movement processing section thatcauses the three-dimensional model of the press machine to moveaccording to the press program; and a robot movement processing sectionthat causes the three-dimensional model of the robot to move accordingto the robot program.
 2. The press working simulator according to claim1, further comprising a press program modification section that modifiesthe press program according to any difference between press machinemovement conditions to be checked and press machine movement conditionsunder which the profile data is recorded.
 3. The press working simulatoraccording to claim 1, further comprising: an interference detectionsection that detects interference between the three-dimensional modelsof the workpiece, the robot, and the press machine; and a robot programmodification section that modifies the robot program to preventinterference detected by the interference detection section.